This work will evaluate polyurethanes for use as maxillofacial prostheses. These materials are readily available and have physical properties compatible with use as extraoral prostheses. Published data on the polyurethane systems indicate that these materials can be adapted to use for prostheses. The major difficulties with most commercially available polyurethane systems is the possible toxicity and uv degradation from the aromatic isocyanate component. We will survey polyurethane systems, including the one presently used (Epithane-3), testing for hardness, modulus, tensile strength, elongation, tear resistance and durability. Computer processing of laboratory data will help to determine if material improvement can be made by compromising some properties to improve deficient ones. This screening and optimization will identify a few promising materials, which will be further evaluated and tested for toxicity. The successful materials will be prepared for clinical use and tested in the Maxillofacial Center. Careful records of patient habits, environment, and use will be used to grade and evaluate deterioration. Feedback from clinic to the laboratory will be used to improve the materials. This process will result in one or more that will be better for prosthetic use than those now in use.